OS18 - Open Session 2018 Borgo Egnazia (Puglia), Italy 29 - 31 /10/2018 EuFMD Sessions\Open Session\Archive-2018\Open 2018 - Italy\6. Online & Streaming\PPTs

1. Modelling the Impact of Regional
Movement Control for FMD
Outbreaks
Mike Tildesley

2. Movement Controls
• Movement restrictions of live animals are
enforced to reduce transmission risk of
infectious diseases.

3. Movement Controls
• Movement restrictions of live animals are
enforced to reduce transmission risk of
infectious diseases.
• For epidemic diseases in the UK, movement
restrictions are typically put in place
nationwide.

4. Movement Controls
• Movement restrictions of live animals are
enforced to reduce transmission risk of
infectious diseases.
• For epidemic diseases in the UK, movement
restrictions are typically put in place
nationwide.
• In some instances, restrictions are “relaxed”
after a period without cases.

5. The UK 2001
Foot and Mouth
Disease Epidemic

6. UK 2001 epidemic timescale
Epidemic peak occurred in
late March/early April.
FMD entered the UK in
early February.
Over 10,000 farms were affected by the epidemic (either infected or
culled as part of the control) and a total of 850,000 cattle and 4,000,000
sheep were culled.
Very long epidemic tail.

7. Spatial spread of Disease
Infected
Farms
2026 premises were infected during the
outbreak (Infected Premises)
Major epidemic hot spots in:
Devon – 172 IPs + 775 control culls
Wales – 113 IPs + 684 control culls
Scottish Borders – 187 IPs + 1266 control culls
Cumbria – 892 IPs + 2952 control culls

8. Foot and Mouth Disease
• For outbreaks of FMD in the UK, nationwide
controls are introduced, regardless of location
of outbreak.

9. Foot and Mouth Disease
• For outbreaks of FMD in the UK, nationwide
controls are introduced, regardless of location
of outbreak.
• In 2001, a delay in introduction of control
caused spread around the country.

10. Foot and Mouth Disease
• For outbreaks of FMD in the UK, nationwide
controls are introduced, regardless of location
of outbreak.
• In 2001, a delay in introduction of control
caused spread around the country.
• In 2007, there were 9 premises infected with
FMD in Surrey.

11. Foot and Mouth Disease
• For outbreaks of FMD, nationwide controls are
introduced, regardless of location of outbreak.
• In 2001, a delay in introduction of control
caused spread around the country.
• In 2007, there were 9 premises infected with
FMD in Surrey.
• In this outbreak, the largest cost of the
outbreak was due to this movement ban.

12. Economic Costs of the Outbreak
The costs of the UK 2001 outbreak can be split into five main
categories:
Direct Costs to the Farmer (compensation and disposal) - £3 billion
Welfare Cull costs - £0.2 billion
Costs to the Wider Agricultural Sector - £0.3 billion
Costs to the Tourist Industry - £5 billion
Export Costs - £0.3 billion
The nationwide movement ban and related restrictions was directly
responsible for increased costs in several of these categories (though
may, of course, have significantly reduced the outbreak size).

13. Are nationwide movement
restrictions always justified for
FMD epidemics?

14. Are nationwide movement
restrictions always justified for
FMD epidemics?
We will use the Warwick FMD
model to simulate the economic
impact of regional movement
control

15. How do we calculate costs?
Direct Costs: Proportional to total livestock culled (~£1200/cattle,
~£320 sheep)
All of these figures have been estimated from the 2002 Anderson
Lessons to be Learned Enquiry (sensitivity to these shown later).
Welfare Costs: Proportional to total number of farms per day subject
to movement restrictions ( ~£5 per Farm Day Restricted)
Agricultural Costs: Proportional to total number of movements
prevented (~£140 per movement prevented)
Export Costs: Proportional to length of the export ban (~£400,000
per day)
Tourism Costs: Proportion to scale of outbreak (~£170 per Farm Day
Restricted)

16. The Warwick Model
 The model was originally used during the 2001 FMD outbreak, to
predict the risk of local spread, after a nationwide movement
ban.
A B
Risk of infection = “Infectiousness” of Farm A
×
“Susceptibility” of Farm B
×
Distance Factor (The closer the farm,
the higher the risk)

17. The Local Spread Model
Sc/s - susceptibility of cattle/sheep.
N i
c/s - number of cattle/sheep on farm i.
Tc,s - Transmission rate of cattle/sheep.
K(dij) - The transmission kernel. A parameter which weights the
probability of infection based on the distance between
farm i and farm j.
Infected j
Probability of infection per day for every susceptible farm is given by:
Prob = 1 - exp - [ScNc,i
pc+ SsNs,i
ps] [TcNc,j
qc + TsNs,j
qs]K(dij)[ ]i
TransmissionRisk
Distance from source
Kernel

18. Modelling Movements
In addition, we want to consider the risk of
transmission via livestock movements.
When a farm is reported, we will consider
the following options:
• No movement control
• Movement ban within a certain radius of
infected premises
• Nationwide movement ban
We utilize data from the cattle tracing scheme and the animal movement license
scheme in the UK to simulate transmission risk via movements.

19. Results
Nationwide movement ban optimal
for minimising direct costs.
Cumbria
Small radius (~20km) movement ban
optimal for minimising overall costs.
Devon
Impact of tourism costs lower in
Devon.
Higher radius movement control
optimal overall.

20. Sensitivity to Cost Assumptions
The presented results are dependent upon the specific costs defined.
We can therefore test the sensitivity of our results to different cost assumptions.
This can be done using our freely accessible Shiny App:
https://livestockmovements.shinyapps.io/movement_control/

21. Sensitivity to Cost Assumptions
https://livestockmovements.shinyapps.io/movement_control/

22. Sensitivity to Cost Assumptions
https://livestockmovements.shinyapps.io/movement_control/

23. Sensitivity to Cost Assumptions
https://livestockmovements.shinyapps.io/movement_control/

24. Sensitivity to Cost Assumptions
https://livestockmovements.shinyapps.io/movement_control/

25. Sensitivity to Cost Assumptions
https://livestockmovements.shinyapps.io/movement_control/

26. Sensitivity to Cost Assumptions
https://livestockmovements.shinyapps.io/movement_control/

27. Sensitivity to Cost Assumptions
https://livestockmovements.shinyapps.io/movement_control/

28. Summary
The evidence suggests that for future outbreaks it may be cost effective not to
ban movements nationwide.
The scale of any future movement ban is dependent upon the region of
introduction and the priorities for control.
Even if indirect (tourism) costs are ignored, radial movement bans are more cost
effective than nationwide bans.
The advantage with regional movement bans is that farmers not immediately
affected by an outbreak can operate “as normal”.

29. Acknowledgements
Matt Keeling (Warwick)
Ellen Brooks Pollock (Bristol)
Sam Brand (Warwick)
Naomi Bradbury (Warwick)
Marleen Werkman (Imperial)